This application claims the priority of German Patent Documents 198 46 117.8 and 198 46 118.6, filed Oct. 7, 1998, the disclosures of which are expressly incorporated by reference herein.
The present invention relates to the use of a material with a high internal damping for a component of a sound-emitting machine. The component is arranged inside or outside the sound-generating or sound-conducting flux of force of the machine.
The high acceleration of mechanically moved parts causes undesirable vibrations in a wide frequency spectrum. This is particularly noticeable in the case of machines with rotating parts, for example, internal-combustion engines. In order to at least reduce such sounds, different solutions are suggested. Thus, for example, particularly in vehicle construction, passive measures are often used, such as damping mats, vibration dampers, and the like. Furthermore, active measures, such as influencing the airborne sound in an occupant compartment (active noise control) by means of acoustic interference is also used for reducing a perceived disturbing sound.
Another measure is known from German Patent Document DE-P 198 26 175, which discloses that it is advantageous to place into a transmission path of a sound (i.e., the flux of force between an exciting component and a component that transmits this excitation to an element radiating the sound, particularly as a disturbing noise), a device by means of which the intensity of the flux of force between the component from which the flux of force originates and the component to which the flux of force is transmitted is at least reduced.
The above-mentioned measures require, among other things, high technological, materials-related, and sometimes also financial expenditures. In addition, these measures increase the overall weight of the machine, which is undesirable, particularly in automobile construction.
It is an object of the present invention to provide a simple possibility for influencing noise emitted from a machine at reasonable cost.
In the case of components which are arranged within the sound-generating or -conducting flux of force, this object is achieved by the use of a material according to the present invention. In the case of components which are arranged outside the sound-generating or -conducting flux of force and act as a membrane for the sound, this object is achieved by the use of a material according to the present invention, in which case such components may be made of these materials only in regions.